Steam engine



March 30, 1937'. -H. J. TITUs ET Al.

STEAM ENGINE Filed May 14, 1928 5 Sheecs--Sheei'I l bbh, @KN QmQ SW B m,b5 SE w EGKS @gy N bwk. QRN b%\ Sw Q March 30, 1937. H. J. TITUS ET ALSTEAM ENGINE Filed May 14, 1928l 5SheetS-Shee1'l 2 INVENT 5 //wd. m BYlul/n ATTORNEYs 5 Sheets-Sheet 5 S TEAM ENGINE H. J. TITUS ET AL FiledMay 14, 192B '7L A TT ORNE YS March 30, 1937.

March 30, 1937.v H. J. TlTus ET AL STEAM ENGINE 5 Sheets-Sheet 4 FiledMay 14, 1928 s s Nm/ R n. m Jg 4f y B March 30, 1937. H. J. TITUs ET AL2,075,069

STEAM ENGINE Filed May 14, 1928 5 Sheets-Sheet 5 l INVENTORS BY M4 lATTONEYS Patented Mar. 3G, i937 UNITEB STATES PATENT GFFICE STEAM ENGINEApplication May 14, 1928, Serial No. 277,772

23 Claims.

This invention relates to steam engines and more particularly to amethod of an apparatus for equalizing or smoothing out the torque insuch engines, and, since it is particularly useful 1 5 in and applicableto locomotives, it will be here.-

in described and illustrated in connection with locomotive constructionand operation.

The objects and advantages of the invention will be better understood ifcertain practical considerations in connection with this art be firstset forth.

In multi-cylinder reciprocating engines there is not only theirregularity or inequality in net torque or rotative effort resultingfrom the con- 5 stant change in thrust of each piston of the engine fromzero to maximum, but there are also inequalities as between the severaltorque peaks themselves in each complete cycle of the engine, whicharise largely from the differences in angular position of the connectingrods in the several quarters of the cycle. For example, in a twocylinder engine, with cranks set at the usual 90 angle to each other,there are (in the combined rotative effort curve) four maximum and fourminimum, i. e. high and low points, or torque peaks and valleys, in eachcycle of the engines operation, but these peaks are not the same. Thehighest quarterly maximum peak occurs during that quarter of the cyclewhen the leading cylinder is working on the head end and its crank is inthe first quarter revolution from its forwardl center, and the followingcylinder is working on the crank end and its crank is in the lastquarter revolution toward its forward center.

If the foregoing quarter cycle be termed the rst quarter, and the otherquarters be numbered thereafter in succession, the lowest quarterlymaximum torque peak occurs in quarter number 3, and the intermediatemaximum peaks in the second and fourth quarters, the second peakordinarily being slightly higher than the fourth. The diiferencesbetween the several minimum torque peaks, i. e., low torque points, arenot so great. In locomotives, such torque inequalities result in atendency of the driving M rough handling of trains in starting.

In connection with locomotive calculations the factor of adhesionordinarily used takes into consideration the average tractive powerdeveloped during a revolution of the drivers. I-IOW- ever, the startingpower which a locomotive can actually deliver is governed by the truefactor of adhesion which takes inte consideration the maximum power, i.e., the highest torque peak, that may be developed during a completerevolution. Heretofore, in order to increase the average starting power,resort has been had either to the expedient of adding drivers to theengine, or else to increasing the weight on the drivers which allows anincrease in the power which can be applied without making the enginemore slippery, b-ut with modern locomotives the number of drivers andthe weight per driver has about reached the practical limit. It ispartly to overcome this difficulty that the three cylinder engine hasbeen introduced, with its increased overlapping of piston thrusts, buteven the use of three cylinders will not obviate substantial differencesbetween the peaks of the torque curve.

We propose, by our invention, to increase the average starting power ofa locomotive by reducing the factor of adhesion, and this without makingthe engine more slippery. In fact, by our invention, an increase in theaverage starting power can be obtained with less tendency toslip thanbefore; or in other words, the true factor of adhesion can actually beincreased while what is normally termed the factor of adhesion is beingreduced. We accomplish the desired result, and overcome to a largeextent the diiiicul ties and disadvantages hereinbefore set forth,preferably by smoothing out the rotative eiTort curve of the locomotivewhile maintaining the true factor of adhesion constant, thus loweringwhat is ordinarily termed the factor of adhesion.

In other words we aim by our invention to smooth out the peaks of therotative effort curve and bring them more nearly in line with theaverage rotative effort, which makes it possible to increase the saidaverage rotative effort without rendering the engine more slippery.

Furthermore we aim by our invention to improve the operation both oftwo-cylinder and three-cylinder engines, and to provide simple andreliable mechanism whereby the desired advantages can be easily andinexpensively attained in existing equipment.

More specifically our invention contemplates the provision of irregularsteam distribution as between the two ends of a cylinder, and/or asbetween different cylinders of an engine, as for Cil , the samelocomotive when running in reverse motion;

Fig. 2 is a graph similar to Fig. l, but of an'- other rotative eifortcurve;

, Fig. 3 is an enlarged longitudinal vertical section through theright-hand of a locomotive valve chest illustrating a cam-operatedpoppet valve mechanism adapted to carry out the invention;

Fig. 4 is a section taken on the line 4 4 of Fig. Y3.

Fig. 5 is a diagrammatic illustration, viewed from the right-hand sideof the locomotive, of certain control mechanism used in connection withthe construction shown in Figs. 3 and 4;

Fig. 6 is an enlarged view, partly in section and partly in elevation,of the admission valve cam of Figs. 3 and 4;

Fig. 7 is a perspective view of the cam, showing a shiftable cam elementlocated out of its normal position in order to illustrate the contoursof the parts;

Fig. 8 is a vertical section through one of the `control valves of Fig.5; and

Fig. 9 is a condensed left-side elevational view of a two-cylinderlocomotive on which the mechanism of this invention has been applied,oertain parts being shown somewhat diagrammatically.

Referring first to the graphs, it will be seen that in Fig. l we haveshown the rotative effort curve of a two-cylinder locomotive having 50%limited cut-oir, through .one complete cycle. The numerals at the leftof the figure indicate rotative effort, in thousands of pounds, andthose at the bottom the degrees of rotation of the drivers. The crankpin positions are indicated at the top, rotation being clockwise, asshown by the arrow, and the right (leading), and left (following), sidesof the engine are indicated by the characters RS and LS, respectively.The lines RCand LC are curves indicating the torque exerted through theright cylinder and crank and vleft cylinder and crank, respectively, andthe curve above these two indicates the total torque, i. e., thecombined rotative effort.

It will be seen that the mean average torque or rotative effort, in thisexample, with a valve cut-off of 50% for both ends of each cylinder, is60,000 lbs., but the torque peaks vary greatly, not only from thisaverage, but also as between themselves, the highest maximum torque peakI, being about 72,000 lbs., which is 19.7% above the mean average, whilethe other high torque peaks, 2, 3 and 4, are approximately 67,000,59,000 and 65,000 lbs., respectively. By altering the cut-off, inaccordance with our invention, to 43% on the crank end of the left(following) cylinder, and to 60% on the head end of the same cylinder,as indicated on the graph, the highest vpeak I is lowered to about theheight oi peak 2, and the lowest high peak 3 is raised to ,o75,oee

about the height of peak 4A. As for the mini" mum or low peaks. whilepeak 5 remains the same and peak 8 is lowered somewhat, peaks B and 'lare both raised. The improvement, in the lowering of the high peak andthe raising of the minimum peak and two of the valleys in the curve, isgraphically shown by the shaded areas. The net change in the averagerotative effort is a rise to the line a, an increase of about 15,00 lbs,and with less tendency to slip.

It will now be seen that along with a rise in two of the low peaks andan increase in the average rotative effort the highest maximum peak hasbeen reduced from 19.7% above mean to about 9.6% above mean. Added powercould now be applied to the cylinders to such an extent a-s to raise themean rotative eiort to approximately 66,500 lbs., that is, until peak iagain reached 72,000 lbs., without rendering the engine any more likelyto slip than it was originally.

By reference now to Fig. la, it will be -seen that we have illustratedthe operation of the same locomotive, when moving in reverse, and whenemploying the preferred embodiment of our invention (as hereinafterdescribed). It will be readily understood (as later pointed out indetail) that when a two-cylinder, reciprocating-engine, locomotive isreversed, the leading side becomes the following side and the followingside becomes the leading side, considered with reference to thedirection of rotation of the crank pins, with a pin on one side of thelocomotive leading a pin on the other side by Similarly to the graph ofFigure 1, the graph of Figure 1a shows, in a solid line (near the top ofthe figure) the combined rotative effort curve of a twocylinderlocomotive with 50% cut-off at each end of each cylinder, but with thelocomotive running in reverse; and showing in dotted lines themodification of that curve by the reversed operation of the preferredembodiment of the present invention.

For convenience of comparison between Figure 1 and Figure la, 'theprogression of the graph of Figure 1a has been made to read from left toright, as in the case of Figure l, and the initial crank pin positions(marked RS for right side and LS for left side) are located the same asin Figure l, that is, with the right crank pinion forward dead center,but the direction of rotation is in a sense opposite to that of Figure41, that is, counterclockwise, as indicated by the arrow.

Since the right cylinder and crank were assumed to be leading in Figurel, it is obvious that the left cylinder and crank will `he leading inFigure la. Now it is clear that since the -modiiied cut-off on the leftcylinder of Figure 1 and the uniform cut-off yon the right cylinder`thereof produce the illustrated improvement in forward motion, thoserelationships must be reversed for reverse motion, if the locomotive isto have the same advantages when operating in reverse as when movingforwardly. Portions of the mechanism later described have been devisedto Vaccomplish this reversed modification o'f the cutoif, and inaccordance therewith the graph vof Figure la shows the left crank torquecurve for 50% cut-off operation (marked H yE for the head end stroke,and vmarked `C E for the crank end stroke), while the curve for theright-hand crank shows in dotted lines the modification obtained by 60%out-off on the head end Vstroke and 43% cut-off Yon the crank endstroke.

The shaded areas show the improvement in the raising of 'the lowesttorque peak and associated depressions of the combined rotative effortcurve, and the reduction of the highest torque peak thereof; theimprovement thus being similar to that shown in Figure l, and sim--ilarly illustrated, the modification of the curve being indicated by thedotted line portions. Tlie net change in the average rotative effort isa rise to the line a, an increase of about 1,500 lbs., just the same asin forward motion which was illustrated in Figure 1.

From the above comparison of Figures 1 and 1a it will be observed thatthe normal curve produced at the left crank, in reverse (Figure la) issubstantially the same as the normal curve at the right crank in forwardmotion (Figure l) and that the normal and modied curves at the rightcrank for reverse (in Figure la) are substantially the same as thenormal and modified curves of the left crank for forward motion (inFigure 1) and that the net results, i. e., improvement in the combinedrotative effort curve, are substantially alike in reverse (Figure la) asin forward motion (Figure 1); when our invention is functioning in itsreversed relationship, according to the direction of motion of thelocomotive. There is, however, one major distinction, namely: thebenefits from the altered cutoff occur between approximately and 90 andbetween 180 and 270, in the forward motion (Figure l), that is, theyoccur substantially in the first and third quarters of a cyclecommencing with the right side crank at forward dead center (forwardwith respect to the locomotive), whereas in reverse the sameimprovements occur in the second and fourth quarters of the cycle,commencing from the same point, that is, with the right side crank atforward dead center (forward with respect to the locomotive). It mighthere be noted that below the graph of Figure la we have indicated thedegrees of rotation, sep arately as to the right crank and the leftcrank, identifying a given point in the cycle by the same degree numberas employed in Figure l, but reading in the reverse order, since thedirection of rotation is opposite.

From the foregoing explanation of Figure l and Fig. la the other graphwill also be readily understood. The graph of Figure 2 illustrates theresults obtained with a 90% cut-off, twocylinder engine, in which thecrank end of the left cylinder has been altered to a '70% cut-olf. Inthis case the highest peak l has been reduced from 23.6% above mean to16.3% above mean, Which is about the same as peak 2. An increase inpower could now be applied to this engine sucient to increase theaverage rotative effort by about 8,000 lbs. with no greater tendency toslip than before the alteration in the cut-off.

In applying the invention to a two-cylinder locomotive engine we haveprovided an oscillating-cam-operated poppet-valve apparatus. The poppetvalve device, while herein shown merely for illustrative purposes-othervalve devices being applicable--has the advantage of full opening of theports even at short limited maximum cut-offs.

Referring now to the illustrative embodiment, Figs. 3 to 9 inclusive, itWill appear that we have devised a modified form of Lentz valvemechanism, arranged to carry out the invention on a two-cylinder engine.Figs. 3 to 8 illustrate the construction for the right hand side of theengine, (embodying in this instance the following crank); While Fig. 9shows the locomotive from the left-hand side (having the leading crank).

In this construction the usual valve rod connection I5 is made to thearm I6a of cam-shaft I9 which extends into the valve chest I1. Thisshaft carries the usual exhaust-valve cam controlling the exhaustthrough outlet 2 which is thus oscillated by the usual valve motionmechanism (a known example of which is shown in Fig. 9) in a mannerknown in the art, which will not here be enlarged upon. Pipe I8b is theusual lubricator pipe for cylinder I 8a.

The admission-valve cam 22, also carried on shaft I9, controls theadmission of steam through inlet 23 and steam chamber 25, by means ofthe annular poppet valves 25, 26, controlling ports 2'! and 28,respectively, at the two ends of the cylinder lBa. These valves, asordinarily used, are slightly overbalanced for closing, and in additionhave adjustable springs 25a and 26a to insure seating when steam isentirely cut off from the steam chamber 24, as when the engine isdrifting. The valves are controlled by cam 22 through the intermediationof their respective stems 29, 30, and cam-engaging rollers or followers29a, 30a.

Cam 22 has no-t only the usual high and low surfaces 3l, 32, withintermediate sloping surfaces 33 and 34, each of the latter of which inthe ordinary construction controls both the admission and cut-off forits particular end of the cylinder, but in our construction this cam isalso equipped with additional cam elements comprising tWo movablesegments 22aI and 22a', mounted on bars 22e slidable in guides 22h,providing additional cam surfaces 3m, 3m, and slopes 33a and 34arespectively.

Upon oscillation of the cam assembly, means of the ordinary valvemotion, in timed relation to the piston stroke, the cam slopes 33 and34a control the cut-off and slopes 33a and 34 the admission of valves 25and 26, when the movable segments 22a and 22a are operating. At timeswhen the movable segments are not operating, the cut-off and admissionare both controlled by slope 33a for valve 25, and by slope 34 for valve26, thus giving substantially equal admission and equal cut-olf for thetwo ends of the cylinder.

In the ordinary Lentz construction, the surface 33a is a fixed part ofcam 22 and normally controls both admission and cut-off through valve 25and port 21; and surface 34 controls the admission and cut-off throughvalve 26 and port 28, either valve being wide open when its cam followerrides on cam face 3|, and entirely closed when its follower rides onface 32. In our construction, on the other hand, where a later cutoff isdesired on the head end of the cylinder (i. e., the following cylinder,as shown in Figs. 3 and 4) and an earlier cut-off on the crank end, thesurface 34 is the admission point for value 26, and the surface 33a theadmission point for valve 25 while the surfaces 34a and 33 provide therequisite cut-off points, respectively, for the two valves. This isaccomplished by the periodic shifting of the segments 22a and 22a intheir guide-ways causing surfaces 3| a to shift into and out of registrywith cam surface 3|.

For the shifting of the cam segments, each is provided, at therespective ends of its sliding bar 22o with an inner and an outer bevelsurface, 35 and 36, respectively, adapted to contact in alternation withco-operating beveled cam shifters 35a and 36a. When the segment 22a` forthe head end of the following cylinder (Which is the segment shown atthe right in Fig. 3) is i.) shifter 35a, a similar cavity 38 is engagedby the plunger 39 to position the segment in its Operative position inline with the cam follower.

A4 similar shifting action takes place in the operation of the segment22a' for the crank end l5 of the following cylinder (which s the lefthand segment shown in Fig. 3), but it should be particularly noted thatthis segment, as shown in dotted lines in Fig. 4, is mounted adjacentthe outside end of its sliding bar 22C, so that when the segment ismoved inward by its shifter 36a.

the surface 3|a of segment 22a will be in line with cam face 3| and thecam follower 29a, and when 22a is moved outward by its shifter 35a itssurface 3|a will be out of line with face 3| l5 and follower 29a.

In other words, the cam segment 22a at the right in Fig. 3, which is forthe head end of the cylinder on the following side of the locomotive,when actuated by shifter 36a is moved in- Si) ward, out of line with thexed cam surface 3| (to the position shown in Fig. 6); while the camsegment 22a at the left in Fig. 3, which is` for the crank end of thecylinder, when similarly actuated by its shifter 36a is moved in- 35Ward, into line with the fixed cam surface 3| (to Ythe position shown inFig. 4). Therefore, upon oscillation of the cam and the periodicShifting of the segments, surfaces 33a and 34 `determine the admissionpoints for the steam,

o and surfaces 33 and 34a the cut-off points, thus giving admission atthe normal time at each end of the cylinder and giving a late cut-offand an early cut-off, respectively, at the head end and crank end of thecylinder. The result is, of

45 course, the desired unequal steam, and consequently power,distribution as between the two ends of the cylinder, whileapproximately (though not exactly) equal or balanced distribution asbetween the two cylinders of the engine,

50 in any complete cycle, is maintained.

For reasons which will hereinafter appear, each shifter member 35a ismovable in guides 46, and is held outward or forward in operativeposition by a motor device comprising a piston 4| acted on by fluidpressure admitted to a cylinder 42 through a suitable pipe 43 (see Fig.4). A spring 44 is provided to move the cam shifter 35a to inoperativeposition when the air or other fluid pressure is cut off from thecylinder 42.

Obviously, when the locomotive is running backward the following sidebecomes the leading side and vice versa. Since, in accordance with ourinvention, the leading side should have equal cut-offs at each end, thefollowing side for forward motion must be altered to give equal cut-offsfor reverse motion. Therefore, when running in reverse, the fluidpressure should be cut off from the cylinders 42 to permit the camShifters 35a to move inward into inoperative position under theinfluence of their springs 44. Cam segments will then be moved inward bythe fixed cam shifting faces 36a, the segment for the head end of thecylinder being held by its plunger 39 in the position shown in Fig. 6,and

il the crank end 'segment 22a being held by its plunger 39 in thecentral position shown in Figs. 4 and 7 with its surface 3|a in linewith cam surface 3|, thus giving substantially equal cutoffs on bothends of the right cylinder, which is now the same as the left cylinder.

Fluid pressure should now be admitted to the motor devices 42 on theleft (leading) side of the engine, which, for reverse, has become thefollowing side, to give unequal cut-offs to the two ends of the cylinderon that side.Y The cylinder and valve structure for the left side of theengine, it should be understood, is similar to the structurehereinbefore described, and therefore the left side (see Fig. 9) isshown only in outline.

The air, or other fluid pressure, admitted to the cylinders 42, may becontrolled in any suitable inanner but we prefer to employ some meansunder the inuence of the reversing mechanism of the locomotive, forexample pilot valves 45, 4B, actuated by movement of the locomotivereverse lever 41, as shown in Figs. 5, 8 and 9. Such pilot valves forcontrolling compressed air are Well known in the art, and an example canbe found in Peters Reissue Patent No. 16,483, dated November 2,3, 1926.In the arrangement here shown, when the reverse lever 41 is moved intoforward position, the trip member 48 actuates the plunger 49 of pilotvalve 45 `(see Fig. 8) to open said valve an-d admit uid pressure, froma suitable source of pressure, such as air tank 5|, through pipe 52 andpipe 43R, to the pipes 43 (shown in Fig.'4) there being one such pipefor each motor cylinder 42, which actuates the pistons 4| to move camShifters 35a into operative position. These shifters, together withshifter surfaces 36a, then cooperate with the cam segments 22a and 22ato slide the latter back and forth, all as previously described, thusgiving the cylinder the desired unequal cut-off as between its two ends.

When the reverse lever 41 is moved into reverse position, the member 48is disengaged from plunger 49 to shut oi the air supply and permitexhaust of the air from cylinders 42 on the right hand side of theengine, and engages plunger 50 of valve 46 to admit air through pipe 52aand pipe 43L to the cylinders 42 on the left hand side of the engine,which, as before said, when running in reverse, becomes the followingside, (in our present example). The left side of the locomotive is shownfragmentarily in Fig. 9, with the various parts of 'our novel structureillustrated in their association with the ordinary running gear andvalve motion mechanism. It might here be noted that the operatingconnection between the reverse lever 41 and the valve gear isillustrated only diagrammatically, as this may take any usual form,including, if desired, a power reverse gear. The left-hand piston, mainrod and crank pin are indicated at LP, LR and LC;I and the correspondingparts for the right side are diagrammatically indicated at RP, RR andRC.

In practice it may be desirable to have an irregular distribution ofpower only when the locomotive is working at late cut-offs, as instarting, and to have ordinary distribution when the engine attainshigher speeds, whether operating forwardly or in reverse. We havetherefore shown the trip 48 on the reverse lever as being comparativelyshort, so that when the reverse lever is taken out of the corner, as itis termed, the pilot valve will close and exhaust the air out ofcylinders 42, springs 44 will retract cam Shifters 35a, and segments 22aand 22a. will move to their idle position, thus yielding substantiallyidentical cut-offs between thev ends of each cylinder and between thecylinders. However, it is obvious that we may make the engaging arms oftrip 48 of any desired length, so as to maintain the irregulardistribution of steam even until very early cut-oils, if desired.

From the foregoing detailed description of Figs. 3 to 9 inclusive, itwill now be quite evident how we obtain the advantages illustrated in,and described with reference to, the graphs of Figs. 1 and 1a, whichillustrate the forward and reverse operation of the locomotive. It willfurther be evident that the invention is particularly advantageousbecause the benets from the change in cut-off are obtained without thenecesf sity of altering the normal crank angles and without any changein the other valve events, and further without altering the valve travelor port opening. In addition, by the control system employed, themodified cut-ofi can always be obtained on the following cylinder,whether operating in forward motion or in reverse; and a hooking back ofthe reverse lever after the locomotive gets under way automaticallyrestores both ends of both cylinders to equal cut-off, resulting in thedesired equality of power output at high speeds.

A portion of the benet results from the earlier cut-off on the crank endof the following cylinder, and a portion of the benefit results from thelater cut-off on the head end of the following cylinder. Where themechanism, as here shown, is capable of producing both these results,there is a very substantial improvement in the operation of thelocomotive, and the steam pressure may actually be stepped-up, ifdesired, without rendering the locomotive any more slippery than it wasoriginally.

From Fig. 2, hereinbefore considered, it will be evident that it ispossible to attain a portion of the advantages of the mechanism even ona locomotive of very late cut-off when in full gear position (having,for example, a cut-olf at 90% of the stroke) by providing an earliercut-olf at the crank end of the following cylinder.

In view of the foregoing it will be evident that, by an unequal steam,and consequently power, distribution, we obtain a marked improvement inthe average rotative effort at slow speeds, so that the locomotive willhave less tendency to slip, or so that the average tractive eifort maybe increased substantially without any greater tendency to slip.

We claimz- 1. In engine mechanism of the character described, a valvechest, valve actuating means therein including movable cam means havinga segment movable with relation thereto, and stop means co-operatingwith said segment to move it periodically upon movement of the cammeans.

2. In engine mechanism of the character described, a valve chest, valveactuating means therein including movable cam means having a segmentmovable with relation thereto, and stop means co-operating with saidsegment to move it periodically upon movement of the cam means, togetherwith control means for said stop means.

3. In reversible engine mechanism of the character described, a valvechest, valve actuating means therein including movable cam means havinga segment movable with relation thereto, and stop means co-operatingwith said segment to move it periodically upon movement of the cammeans, together with control means for said stop means under the inuenceof the engine reversing mechanism.

4. In reversible engine mechanism of the character described, a valvechest, valve actuating means therein including movable cam means havinga segment movable with relation thereto, and stop means co-operatingwith said segment to move it periodically upon movement of the cammeans, together with control means for said stop means under theinfluence of the engine reversing mechanism and adapted to render saidstop means inoperative at high speeds of the engine.

5. A single-expansion double-acting steam locomotive engine having aplurality of cylinders with their pistons, respectively of substantiallyequal diameters and equal strokes; for each cylinder, main steamdistribution valve mechanism and steam portage controlled thereby andopening into the two ends of the cylinder; valve gear means operativelyconnected with said mechanisms for actuating the same in timed relationwith the stroke of the pistons and setto effect a predetermined nominalor maximum normal cut-oilc of a given predetermined percentage value ofthe piston stroke which is substantially identical at both ends of eachcylinder; the valve gear means having reversing apparatus for reversingthe direction of operation of the locomotive; cranks to which thepistons are operatively connected, said cranks being angularly set oneto another and the connecting means between the pistons and their cranksbeing thus positioned to assume relatively different angles at variouspoints in the cycle of operation of the locomotive engine, wherebymarked differences in the combined rotative effort of said plurality ofcylinders considered together occur at different points in the cycle ofoperation of the locomotive engine, so that the combined rotative eiortcurve presents substantial differences between the high and low pointsthereof; mechanism for reducing the spread between some of the high andlow points of the combined rotative effort, during the lower range ofoperating speeds of the locomotive, including means for altering theeffective cut-off point of said distribution valve mechanism at one endof one cylinder as compared with said predetermined normal cut-off ofthe distribution valve mechanism at the corresponding end of anothercylinder without altering the total stroke of the valve mechanism; saidmeans being so arranged that the total work of the cylinders may beincreased to produce a higher average tractive power without loweringthe true factor of adhesion of the locomotive; and means for renderingsaid alteration of cut-off ineffective during the higher range ofoperating speeds of the locomotive.

6. A single-expansion double-acting steam locomotive engine having aplurality of cylinders with their pistons, respectively of substantiallyequal diameters and equal strokes; for each cylinder, main steamdistribution valve mechanism and steam portage controlled thereby andopening into the two ends of the cylinder; valve gear means operativelyconnected with said mechanisms for actuating the same in timed relationwith the stroke of the pistons and set to effect a predetermined nominalor maximum normal cut-off of a -given predetermined percentage value ofthe piston stroke which is substantially identical at both ends of eachcylinder; the valve gear means having reversing apparatus for reversingthe direction of operation of the locomotive; cranks to which thepistons are operatively connected, said cranks being angularly set oneto another and the connecting means between the pistons and their cranksbeing thus positioned to assume relatively different angles at variouspoints in the cycle of operation of the locomotive engine, wherebymarked differences in the combined rotative effort of said plurality ofcylinders considered together occur at different points in the cycle ofoperation of the locomotive engine, so that the combined rotative effortcurve presents substantial differences between the high and low pointsthereof; mechanism for reducing the spread between some of the high andlow points of the combined rotative effort, during the lower range ofoperating speeds of the locomotive, including means for altering theeffective cut-off point of said distribution valve mechanism at one endof one cylinder as compared with said -predetermined normal cut-off ofthe distribution valve mechanism at the corresponding end cf anothercylinder without altering the total stroke of the valve mechanism; saidmeans being so arranged that the total work of the cylinders may beincreased to produce a higher average tractive power Without loweringthe true f factor of adhesion of the locomotive; and means for obtaininga like effect by a similarly altered cut-off in reverse operation.

7. A single-expansion double-acting steam locomotive engine having aplurality of cylinders with their pistons, respectively of substantiallyequal diameters and equal strokes; for each cylinder, main steamdistribution valve mechanism and steam portage controlled thereby andopening into the two ends of the cylinder; valve gear means operativelyconnected with said mechanisms for actuating the same in timed relationwith the stroke of the pistons and set to effect a predetermined nominalor maximum normal cutoff of a given predetermined percentage Value 0fthe piston stroke which is substantially identical at both-ends of eachcylinder; the valve gear means having reversing apparatus for reversingthe direction of operation of the locomotive; cranks to which thepistons are operatively connected, said cranks being angularly set onet0 another and the connecting means between the pistons and their cranksbeing thus positioned to assume relatively different angles at variouspoints in the cycle of operation of the locomotive engine, wherebymarked differences in the combined rotative effort of said plurality ofcylinders considered together occur at different points in the cycle ofoperation of the locomotive engine, so that the combined rotative effortcurve presents substantial. differences between the high and low pointsthereof; mechanism for reducing the spread between some of the high andlow points of the combined rotative effort, during the lower range ofoperating speeds of the locomotive, including means for altering theeffective cut-ofi point of said distribution valve mechanism at one endof one cylinder as compared with said predetermined normal cut-off ofthe distribution valve mechanism at the corresponding end of anothercylinder Without altering the total stroke of the valve mechanism; saidmeans being so arranged that the total Work of the cylinders may beincreased to produce a higher average tractive power without loweringthe true factor of adhesion of thev locomotive; means for obtaining alike effect by a similarly altered cut-off in reverse operation; andmeans for rendering said alteration of cutoff ineffective during thehigher range of operating speeds of the locomotive.

8. A reversible steam engine having a pair of cylinders one of which isa leading cylinder and the other a following cylinder in one directionof motion and vice versa in the opposite direction of motion, steamadmission valve means for said cylinders having means for setting thesame to produce a predetermined normal maximum cutoff the same for bothends of both cylinders,`

mechanism adapted to shorten the cut-off on the crank end and lengthenthe cut-off on the head end of either cylinder as compared with thecutoff on the two ends of the other, and control means adapted toselect, as between said cylinders, which shall have the modifiedcut-offs.

9. A reversible steam engine having a pair of cylinders one of which isa leading cylinder and the other a following cylinder in one directionof motion and vice versa in the opposite direction of motion, steamadmission valve means for said cylinders having means for setting thesame to produce a predetermined normal maximum cutoff the same for bothends of both cylinders, mechanism adapted to shorten the cut-off on thecrank end and lengthen the cut-off on the head end of either cylinder ascompared with the cutoff on the two ends of the other, and automaticcontrol means actuated under the influence of the direction of motion ofthe engine to select the following cylinder and effect said alteredcut-off on that cylinder only.

10. A reversible steam engine having a pair of cylinders one of which isa leading cylinder and the other a following cylinder in one directionof motion and vice Versa in the opposite direction of motion, steamadmission valve means for said cylinders having means for setting thesame to produce a predetermined normal maximum cutoff the same for bothends of both cylinders, mechanism adapted to shorten the cut-off on thecrank end and lengthen the cut-off on the head end of either cylinder ascompared with the cutoff on the two ends of the other, control meansadapted to select, as between said cylinders, which shall have themodified cut-ofs, and means operative under the influence of shorteningof the normal cut-oif of the locomotive to render said mechanisminoperative.

l1. A reversible steam engine having a pair of cylinders one of which isa leading cylinder and the other a following cylinder in one directionof motion and vice versa in the opposite direction of motion, steamadmission valve means for said cylinders having means for setting thesame to produce a predetermined normal maximum cutoff the same for bothends of both cylinders, mechanism adapted to` shorten the cut-off on thecrank end and lengthen the cut-off on the head end of either cylinder ascompared with the cutoff on the two ends of the other, automatic controlmeans actuated under the influence of the direction of motion of theengine to select the following cylinder and effect said altered cut-ofion that cylinder only, and means operative under the influence ofshortening of the normal cutoff of the locomotive to render saidmechanism inoperative.

12. A simple multiple cylinder engine having admission valves for thecylinders, means automatically acting to effect a substantial differingpower distribution to one cylinder as compared with another during acomplete cycle when operating at late valve cut-off, and meansautomatically acting to effect equal and regular power distribution asto, each cylinder at a reduced valve cut-off.

13, In a multiple cylinder locomotive, the combination of cylinders,valve chests, valves, main steam passages, valve gear, a reverse gearcontrolling the valve gear in synchronous movement and including areverse lever, means associated with the valves for effecting adifference in the cut-oi as between cylinders and means associated withthe reverse gear to determine which cylinder shall have the greatestcut-off, said last mentioned means automatically operating the rstmentioned means upon movement of the reverse lever.

14. In a locomotive, the combination of cylinders, valve chests, valvemechanism, main steam passages at the ends of the cylinders, valve gear,reverse mechanism for the valves, means associated with the valvemechanism for effecting an earlier cut-ofi on the steam passage at thecrank end of either of the cylinders, and control means for determiningwhich cylinder shall have the early cut-off on the crank end.

15. In a locomotive, the combination of cylinders, valve chests, valvemechanism, main steam passages at the ends of the cylinders, valve gear,reverse mechanism for the valves, means associated with the valvemechanism for effecting an earlier cut-off on the steam passage at thecrank end of either of the cylinders, and control means for determiningwhich cylinder shall have the early cut-off on the crank end, suchcontrol means being under the iniiuenoe of the reverse mechanism.

16. In a locomotive, the combination of cylinders, valve chests, mainvalve mechanism, main steam passages at the ends of the cylinders, valvegear, reverse mechanism, the valve mechanism being set to giveapproximately equal cut-off at both ends of the cylinders when the valveis in full travel, means controlling the valve mechanism to effect anearlier cut-off of the valve at one end of a cylinder than at the otherand control means for determining which cylinder shall have such earliercut-olf.

1'?. In a locomotive, the combination of cylinders, valve chests, mainvalve mechanism, main steam passages at the ends of the cylinders, valvegear, reverse mechanism, the valve mechanism being set to giveapproximately equal cut-off at both ends of the cylinders when the valveis in full travel, means controlling the valve mechanism to eiect anearlier cut-off for theV valve at one end of a cylinder and a latercut-off for the valve at the opposite end than the nominal cutoff forfull travel, together with means for determining which cylinder shallhave such altered cut-01T.

18. In a locomotive, the combination with the cylinders, main valves,valve chests, valve gear, and reversing apparatus operating all valvessimultaneously and providing a full gear travel of the valves of apredetermined normal maximum cut-off, of mechanism for increasing thatnormal cut-off at one end of a cylinder and reducing that normal cut-offat the other end of the cylinder, means for simultaneously retaining thefull gear cut-off on the other cylinder, control means for saidmechanism and means associated with the reversing apparatus forinitiating and discontinuing the action of said control means.

19. In a locomotive having cylinders, main inlet valves, valve chests,and valve gear and reversing apparatus for operating the valves andproviding a predetermined normal maximum operating cut-off; a movablecam actuated by said valve gear for operating a main inlet valve, saidcam having a high and transition surface for holding the valve from theseat and a low surface for closure or seating of the valve and anintermediate surface to hold the valve from its seat beyond the normalpoint of closure.

20. In a locomotive having cylinders, main inlet valves, Valve chests,and valve gear and reversing apparatus for operating the valves andproviding a predetermined normal maximum operating cut-off; a movablecam means for operating a main inlet valve, said cam means having a highsurface and a low surface respectively operating for opening and closureof said valve, a cam follower connected to said valve and positioned toride on the cam surface, and a shiftable cam element providing for thecam follower to ride on the higher or lower cam surfaces for a greaterdistance at starting than for normal operation.

21. In a locomotive having cylinders, main inlet valves, valve chests,and valve gear and reversing apparatus for operating the valves andproviding a predetermined normal maximum operating cut-oir; a movablecam means for operating a main inlet valve, said cam means having a highsurface and a low surface respectively operating for opening and closureof said valve, a cam follower connected to said valve and positioned toride on the cam surfaces, a shiftable cam element providing for the camfollower to ride on the higher or lower cam surfaces for a greaterdistance at starting than for normal operation, means for shifting thecam element for starting into or out of the path of the cam follower andmeans resisting the placing of the shiftable cam element in positionother than for normal running operation of the locomotive.

22. In a locomotive having cylinders, main inlet valves and valve gearwith reversing apparatus, movable cams actuated by the valve gear foroperating the main inlet valves, the leading cylinder havingapproximately equal cut-offs at both ends of the cylinder, meansassociated with the following cylinder to effect an earlier cut-off onthe crank end and a later cut-ofi on the head end with relation to thecut-off on the leading cylinder, and control means automaticallyoperative upon reversal of the reversing apparatus for determining whichcylinder shall have the altered cut-offs.

23. In a limited cut-off steam engine having cylinders, main inletvalves, valve chests and valve gear for operating the valves andproviding a predetermined normal maximum operating cutoff; a movable camactuated by said valve gear for operating a main inlet valve, said camhaving a high and transition surface for holding the valve from its seatup to the point of normal cut-01T and a low surface for closure orseating of the valve and an intermediate surface to hold the valve fromits seat beyond the normal point of closure, said intermediate surfaceoperating to prevent the lifting of the valve from its seat before thenormal point of admission.

HUBERT J. TI'IUS. JOHN S. WALLIS.

